<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>prototype</title>
</head>
<script>
    function F(){}
        console.log(F.prototype)
        F.prototype.sayHi=function () {
            console.log("Hi")
        }
        var p1=new F()
        var p2=new F("just do it")
        console.log(p1)
        console.log(p2)

</script>
<body>

</body>
</html>